Classification of hydraulic actuators

Classification of hydraulic actuators
Hydraulic control systems can be classified from different perspectives, and each classification method represents certain characteristics of hydraulic control systems.
Classified according to the variation pattern of input signals: fixed value control systems, program control systems, and servo control systems. The hydraulic control system of the hydraulic servo in this article belongs to the servo control system. A servo control system, also known as a servo system, has an input signal that is an unknown function of time. However, the output of a hydraulic control system can accurately and quickly reproduce the changes in the input. Whether a servo system can obtain a fast response is often its main contradiction.
According to the controlled physical quantity, it can be divided into speed control system, position control system, acceleration control system, force control system, and other physical quantity control systems.

Classified by the form of signal transmission medium and the energy form of signals in hydraulic control systems: mechanical hydraulic control (referred to as machine hydraulic control) system, electrical hydraulic control (referred to as electric hydraulic control) system, and pneumatic hydraulic control (referred to as pneumatic hydraulic control) system. The hydraulic control system of the hydraulic servo in this article is an electrical hydraulic control system. In the electrical hydraulic control system, electrical and electronic components are mostly used for the detection, correction, and initial amplification of error signals. Its advantage is that the measurement, correction, and amplification of signals are relatively convenient, easy to achieve remote operation, and easy to integrate with hydraulic power components with fast response speed and high load resistance rigidity, forming an electro-hydraulic control system with electronic and electrical as nerves and hydraulic as muscles. The combination of electrical, electronic technology, and hydraulic control makes the electro-hydraulic control system highly flexible and widely adaptable, making it the current control system with good response speed and control accuracy.
Classified by the type of control components: valve control system and pump control system. Valve control system is further divided into valve controlled hydraulic cylinder system and valve controlled hydraulic motor system. Pump control system can also be divided into variable pump system and variable hydraulic motor system. The advantages of valve control systems are fast response speed and high control accuracy, while the disadvantages are low efficiency; Valve control systems are widely used in fast and high-precision small and medium-sized power applications. The advantages of pump control systems are high efficiency, while the disadvantages are slow response speed and complex structure, making them suitable for situations with high power (above 20kW) and low response speed requirements.